Apparatus and method for controlled delivery of slurry to a region of a polishing device

ABSTRACT

A polishing pad and/or platen for use in a chemical mechanical polishing system is provided. The polishing pad and/or platen have slurry distribution/retaining grooves formed on a surface thereof. In one embodiment, the grooves are formed on the upper polishing surface of a pad for use in a rotary or linear polishing system. In another embodiment, an upper mounting surface of a platen is patterned with grooves. The grooves are adapted to direct the flow of slurry inwardly from a perimeter portion of the pad/platen. In operation, the grooves provide uniform distribution of slurry to areas on a polishing pad/platen.

RELATED APPLICATIONS

[0001] This application claims priority to provisional applicationSerial No. 60/170,596, filed Dec. 13, 1999.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to an apparatus and method forpolishing substrates. More particularly, the invention relates to aplaten/polishing pad assembly having a patterned surface to control thedelivery of slurry onto a polishing surface of a pad.

[0004] 2. Background of the Related Art

[0005] In the fabrication of integrated circuits and other electronicdevices, multiple layers of conducting, semiconducting and dielectricmaterials are deposited and removed from a substrate during thefabrication process. Often it is necessary to polish a surface of asubstrate to remove high topography, surface defects, scratches orembedded particles. One polishing process is known as chemicalmechanical polishing (CMP) and is used to improve the quality andreliability of the electronic devices formed on the substrate.

[0006] Typically, the polishing process involves the introduction of achemical slurry onto a polishing pad during the polishing process tofacilitate higher removal rates and selectivity between films on thesubstrate surface. In general, the polishing process involves holding asubstrate against a polishing pad under controlled pressure, temperatureand rotational velocity of the pad in the presence of the slurry orother fluid medium. One polishing system that is used to perform CMP isthe MIRRA® System available from Applied Materials, Inc., and shown anddescribed in U.S. Pat. No. 5,738,574, entitled, “Continuous ProcessingSystem for Chemical Mechanical Polishing,” the entirety of which isincorporated herein by reference.

[0007] An important goal of CMP is achieving uniform planarity of thesubstrate surface. Uniform planarity includes the uniform removal ofmaterial from the surface of substrates as well as removing non-uniformlayers which have been deposited on the substrate. Successful CMP alsorequires process repeatability from one substrate to the next. Thus,uniformity must be achieved not only for a single substrate, but alsofor a series of substrates processed in a batch.

[0008] Substrate planarity is dictated, to a large extent, by theconstruction of the CMP apparatus and the composition and constructionof the consumables such as the slurry and the pads all of whichcontribute to the polishing rate. One factor which contributes to theunpredictability and non-uniformity of the polishing of the chemicalmechanical polishing process is the non-homogeneous replenishment anddistribution of slurry at the interface of the substrate and thepolishing pad. The slurry is primarily used to enhance the materialremoval rate of selected materials from the substrate surface. As afixed volume of slurry in contact with the substrate reacts with theselected materials on the substrate surface, the slurry constituents areconsumed. Accordingly, the slurry becomes less reactive and thepolishing enhancing characteristics of the slurry are significantlyreduced. Further, because the edge of the substrate contacts the slurryprior to the center of the substrate, the slurry reaching the center isless reactive than the fresh slurry supplied to the edge. Thus, theremoval rate of material over the surface of the substrate isnon-uniform and typically results in center-slow polishing. Attemptingto compensate for the center-slow polishing effect by increasing thepressure applied to the center portion of the substrate compromises theplanarity of the substrate.

[0009] One approach to overcoming the problem of replenishment of freshslurry to all areas of the substrate is to continuously provide freshslurry onto the polishing pad. However, because of the physicalconfiguration of the polishing apparatus, introducing fresh slurry intothe area of contact between the substrate and the polishing pad isdifficult, and providing a consistently fresh supply of slurry to allportions of the substrate and the polishing pad is even more difficult.As a result, the uniformity and overall rate of polishing aresignificantly affected as the slurry reacts with the substrate.

[0010] Another problem with continuously providing fresh slurry onto thepolishing pad is the volume of slurry that is consumed. In order tominimize the cost of operation, the volume of slurry used in aprocessing cycle should be minimized. However, conventional pads are notcapable of efficiently retaining the slurry between the pad and thesubstrate. The inertia of the slurry during the rotation of the padcauses the slurry to flow off of the pad during operation. Thus,conventional practice dictates continuously providing fresh slurry ontothe polishing pad. As a result, the volume of consumed slurry issubstantially higher than is desirable.

[0011] One solution to remedy the problem of poor slurry distributionhas been to provide grooves in the pad. One grooved pad is the IC 1000pad available from Rodel, Inc., of Newark, Del. The grooves of the IC1000 pad are in an X-Y configuration in the upper polishing surface ofthe pad and are believed to control the distribution of the slurryduring operation by retaining a portion of the slurry in the grooves.However, while such pad designs accommodate more slurry volume, the padshave proved inefficient because the slurry flows radially outward andoff of the pad during rotation of the pad. As a result, conventionalpolishing pads continue to consume large volumes of slurry, therebysubstantially increasing the cost of operation.

[0012] Therefore, there is a need for a polishing pad capable ofcontrolling slurry distribution over the pad surface and providinguniform and planar polishing.

SUMMARY

[0013] The present invention generally provides an apparatus forpolishing a substrate which improves the distribution of slurry over thesurface of a polishing pad and improves uniformity and planarity of thepolishing process. In one embodiment, the apparatus is adapted forincorporation into a chemical mechanical polishing system.

[0014] In one aspect of the invention, a polishing pad is providedhaving an upper polishing surface and a lower mounting surface. Aplurality of fluid delivery grooves is formed in at least one of thesurfaces. The grooves are adapted to control the distribution of fluidduring movement of the pad.

[0015] In another aspect of the invention, a platen is providedcomprising a patterned surface for mounting a polishing pad thereon. Thepatterned surface is defined by a plurality of grooves formed on thesurface which are adapted to control the distribution of fluid duringmovement of the platen. In one embodiment, a pad may be disposed on thepatterned surface. Delivery of fluid to an upper polishing surface ofthe pad is facilitated by pores formed in the pad which couple thegrooves to the upper surface of the pad.

[0016] In another aspect of the invention, the delivery of slurry iscontrolled to provide a greater volume of slurry to a desired locationon the pad. During rotation of the pad, a patterned surface of a pad orplaten is adapted to induce the slurry to flow inwardly away from anedge of the pad or platen.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] So that the manner in which the above recited embodiments andfeatures of the present invention are attained and can be understood indetail, a more particular description of the invention, brieflysummarized above, may be had by reference to the embodiments thereofwhich are illustrated in the appended drawings.

[0018] It is to be noted, however, that the appended drawings illustrateonly typical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

[0019]FIG. 1 is a schematic view of a CMP system.

[0020]FIG. 2 is a schematic view of a polishing station.

[0021]FIG. 3 is a top view of one embodiment of a polishing pad.

[0022]FIG. 4 is a top view of another embodiment of a polishing pad.

[0023]FIG. 5 is a top view of another embodiment of a polishing pad.

[0024]FIG. 6 is a top view of another embodiment of a polishing pad.

[0025]FIG. 7 is a top view of another embodiment of a polishing pad.

[0026]FIG. 8 is a top view of a polishing pad for use with a lineardrive system.

[0027]FIG. 9 is a cross sectional view of a polishing pad taken alongthe width of a groove formed in the pad.

[0028]FIG. 10 is a cross sectional view of a polishing pad taken alongthe length of a sloped groove formed in the pad.

[0029]FIG. 11 is a partial perspective view of a platen and a paddisposed on the platen, wherein the pad has a patterned lower surface.

[0030]FIG. 12 is a partial perspective view of a platen having apatterned surface and a pad disposed on the platen.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0031] The present invention generally relates to a polishing pad and/ora platen having slurry distribution/retaining grooves formed thereon. Inone embodiment, the grooves are formed on the upper polishing surface ofa pad for use in a rotary or linear polishing system. In anotherembodiment, an upper mounting surface of a platen is patterned withgrooves. The grooves are adapted to direct the flow of slurry inwardlyfrom a perimeter portion of the pad/platen. In operation, the groovesformed in the pad/platen provide controlled distribution of slurry. Inone aspect, a relatively higher volume of slurry may be provided todesired areas of the pad to facilitate a higher removal rate of materialfrom a substrate at those areas or more uniform removal rate of materialacross the surface of a substrate.

[0032] For clarity and ease of description, the following descriptionrefers primarily to a CMP system. However, the invention is equallyapplicable to other types of processes that utilize a pad for polishingor cleaning a substrate.

[0033]FIG. 1 is a schematic view of a CMP system 30, such as a MIRRA®System available from Applied Materials, Inc., located in Santa Clara,Calif. The system 30 includes three polishing stations 32 and a loadingstation 34. Four polishing heads 36 are rotatably mounted to a polishinghead displacement mechanism 37 disposed above the polishing stations 32and the loading station 34. A front-end substrate transfer region 38 isdisposed adjacent to the CMP system and is considered a part of the CMPsystem, though the transfer region 38 may be a separate component. Asubstrate inspection station 40 is disposed in the substrate transferregion 38 to enable pre and/or post process inspection of substratesintroduced into the system 30.

[0034] Typically, a substrate is loaded on a polishing head 36 at theloading station 34 and is then rotated through the three polishingstations 32. The polishing stations 32 each comprise a rotating platen41 having polishing or cleaning pads mounted thereon. One processsequence includes a polishing pad at the first two stations and acleaning pad at the third station to facilitate substrate cleaning atthe end of the polishing process. At the end of the cycle, the substrateis returned to the front-end substrate transfer region 38 and anothersubstrate is retrieved from the loading station 34 for processing.

[0035]FIG. 2 is a schematic view of a polishing station 32 and polishinghead 36 used to advantage with the present invention. The polishingstation 32 comprises a pad 45 secured to an upper surface of a rotatableplaten 41. The pad 45 is preferably made of a plastic or foam such aspolyurethane, but other materials known and unknown may be used.Although shown here as a single layer pad, it is understood that inother embodiments the pad may be a composite pad comprising multiplelayers. The platen 41 is coupled to a motor 46 or other suitable drivemechanism to impart rotational movement to the platen 41. Duringoperation, the platen 41 is rotated at a velocity V_(P) about a centeraxis X. The platen 41 can be rotated in either a clockwise orcounterclockwise direction.

[0036]FIG. 2 also shows the polishing head 36 mounted above thepolishing station 32. The polishing head 36 supports a substrate 42 forpolishing. The polishing head 36 may comprise a vacuum-type mechanism tochuck the substrate 42 against the polishing head 36. During operation,the vacuum chuck generates a negative vacuum force behind the surface ofthe substrate 42 to attract and hold the substrate 42. The polishinghead 36 typically includes a pocket (not shown) in which the substrate42 is supported, at least initially, under vacuum. Once the substrate 42is secured in the pocket and positioned on the pad 45, the vacuum can beremoved. The polishing head 36 then applies a controlled pressure behindthe substrate, indicated by the arrow 48, to the backside of thesubstrate 42 urging the substrate 42 against the pad 45 to facilitatepolishing of the substrate surface. The polishing head displacementmechanism 37 rotates the polishing head 36 and the substrate 42 at avelocity V_(S) in a clockwise or counterclockwise direction, preferablythe same direction as the platen 41. The polishing head displacementmechanism 37 also preferably moves the polishing head 36 radially acrossthe platen 41 in a direction indicated by arrows 50 and 52.

[0037] With reference to FIG. 2, the CMP system also includes a chemicalsupply system 54 for introducing a chemical slurry of a desiredcomposition to the polishing pad 45. In some applications, the slurryprovides an abrasive material which facilitates the polishing of thesubstrate surface, and is preferably a composition formed of solidalumina or silica. During operation, the chemical supply system 54introduces the slurry, as indicated by arrow 56, on the pad 45 at aselected rate. In other applications the pad 45 may have abrasiveparticles disposed thereon and require only that a liquid, such asdeionized water, be delivered to the polishing surface of the pad 45.

[0038] In one embodiment, the invention provides a patterned polishingsurface of the pad 45 for controlling the flow of a fluid such as slurryor deionized water. FIG. 3 show a top view of one embodiment of apolishing pad 45A having a patterned surface formed thereon. Thepatterned surface is defined by a plurality of equally spaced fluiddistribution/retaining grooves 60 formed in the polishing surface of thepad 45A. The grooves 60A are arcuate, or tubine-shaped, and extend froman initial end 62A at the edge of the pad 45A to a terminal end 64A nearthe center C_(pad) of the pad 45A. In the embodiment of FIG. 3, thegrooves 60A are not sealed, or blocked, at the initial end 62A. Such anembodiment facilitates construction of the grooves 60A which are milledout by conventional methods such as by a milling bit. However, thegrooves 60A can be sealed at their respective initial ends 62A. Further,the grooves may be formed by alternative methods such as molding the pad45 with cast having the desired pattern.

[0039] The grooves 60A are oriented and shaped to facilitate fluid flowfrom the initial end 62A inwardly to the terminal end 64A. The grooves60A are formed in the pad 45A so that when the pad 45A is rotated in thedirection ω, slurry is flowed toward the center C_(pad) as indicated bythe arrow 71. That is, moving along the length of the grooves 60A fromthe terminal end 64A to the initial end 62A, the grooves 60A are curvedin a clockwise direction which corresponds to the direction of rotationω. Further, a radial line 68 originating at the center C_(pad) of thepad 45A indicates that no point of the grooves 60A is tangent to theradial line 68 except the terminal ends 64A. The curvature of thegrooves 60A is indicated by an angle θ₁ which is defined by the angularrelation between the radial line 68 and a tangent point on the groove60A. As shown in FIG. 3, θ₁ decreases moving inward along the grooves60A toward center C_(pad).

[0040] In general, θ₁ is selected to cause fluid flow through thegrooves 60A during rotation of the pad 45A. During rotation, fluid fromthe chemical supply system 54 is “scooped up” and flowed through thegrooves 60A inwardly toward C_(pad) in the direction of arrow 71. As thecurvature of the grooves 60A approaches a point tangent to radial line68, the fluid decreasingly experiences the necessary force to flow thefluid inward toward the terminal end 64A. The rate at which fluid isflowed through the grooves is generally dependent on the radial positionof the fluid on the pad 45A, the angular velocity of the pad 45A, theviscosity of the fluid, and θ₁. Persons skilled in the art willempirically determine optimal values for these and other parameters.

[0041] The slurry initially collects at a point along the length of thegrooves 60A until sufficient pressure accumulates to flow the slurry outof the grooves 60A and onto the upper surface of the pad 45A.

[0042] The grooves 60A shown in the embodiment of FIG. 3 are constructedto supply slurry toward a central collection area 76A (represented bydashed lines) of the pad 45A. The slurry collection area 76A is definedby that area of the pad 45A where a relatively increased volume ofslurry is delivered due to the presence of the slurry distributiongrooves 60A. The slurry collection area 76A may be determined by theposition of the terminal end 64A or where the slurry is forced onto theupper surface of the pad due to accumulation of the slurry in thegrooves 60A (e.g., where the grooves 60A are tangent to the radial line68). Thus, in FIG. 3 the slurry flows through the grooves 60A and thenonto the upper polishing surface of the pad 45A at the terminal ends 64Aduring operation.

[0043]FIG. 4 shows another embodiment of a pad 45B having grooves 60Bsimilar to grooves 60A of FIG. 3 except that the terminal ends 64B arepositioned further radially outwardly from the center C_(pad) of the pad45B. Accordingly, the slurry collection area 76B (shown by dashed lines)is an annular region substantially commensurate with the positioning ofthe terminal ends 64B.

[0044] Another embodiment, shown in FIG. 5, provides an example ofgrooves 60C having the same direction of curvature and having a tangentpoint 80 to the radial line 68. The tangent point 80 demarks twosegments 82, 84 of the grooves 60C. A first segment 82 extends from theinitial end 62C to the tangent point 80 and a second segment 84 extendsfrom the tangent point 80 to the terminal end 64C. The curvatures of thesegments 82, 84 are indicated by angles θ₂ and θ₃, respectively. Movingalong the grooves 60C toward the tangent point 80 from the initial end62C, θ₂ decreases. Moving along the grooves 60C away from the tangentpoint 80 from the terminal end 64C, θ₃ increases. Thus, θ₂ is greaterthan zero degrees and less than 90 degrees relative to the radial line68 and θ₃ is greater than 90 degrees and less than 180 degrees relativeto the radial line 68. The first segment 82 induces fluid flow from theinitial end 62C to the tangent point 80 in the manner described abovewith reference to FIG. 3. The fluid flow along the first segment 82 isrepresented by an arrow 86 during a direction of rotation ω. The secondsegment 84 curves away from the radial line 68 so that the segment 84 isoriented to avoid intersecting the center C_(pad). In operation, thesecond segment 84 induces fluid to flow in the direction of the arrows88. As a result, fluid flows inwardly (arrow 86) toward the tangentpoint 80 along the first segment 82 and outwardly (arrow 88) toward thetangent point 80 along the second segment 84. The resulting fluid flowthrough the grooves 60C produces a concentration of fluid in thecollection area 76C (shown with dashed lines).

[0045] In another embodiment, the grooves 60 may be of varying geometricconstruction to provide multiple separate, or one larger, slurrycollection area. For example, FIG. 6 shows a pad 45D combining thegrooves 60A (described with reference to FIG. 3) and grooves 60C(described with reference to FIG. 5). Grooves 60A provide slurry to acentral area of the pad 45D (as shown by the area 76A in FIG. 3) andgrooves 60C provide slurry to an annular area of the pad 45D (as shownby the area 76C in FIG. 5). Thus, the combination of grooves 60A and 60Cprovides an aggregate slurry collection area 76D. Other variations arecontemplated to control the distribution of slurry on the upper surfaceof the polishing pad 45.

[0046] While FIGS. 3-6 show grooves 60A-C having a generally curvilinearshape, in other embodiments the grooves may be linear. For example, FIG.7 shows linear grooves 60E having an initial end 62E at the edge of thepad 45E and extending linearly inwardly to a terminal end 64E. Theposition of the terminal end 64E determines where the increased slurryconcentration is formed during operation and is shown here by the slurrycollection area 76E. In order to facilitate fluid flow from the initialend 62E to the terminal end 64E, the grooves 60E are oriented in anon-parallel relation relative to a radial line 68 extending from theinitial end 62E of the grooves 60E to the center C_(pad) of the pad 45E.Accordingly, the grooves 60E are oriented to avoid intersecting thecenter C_(pad) of the pad 45E.

[0047] In another embodiment, the slurry distribution grooves 60 of theinvention may be provided on a pad for use with a linear polishingassembly. FIG. 8 shows a partial top view of the upper polishing surfaceof a linearly actuated pad 45F mounted on a pair of rollers 85 (shown byhidden lines). The rollers 85 are rotated by actuators (not shown) todrive the pad in the direction V, much like a conventional belt drive.The pad 45F includes V-shaped grooves 60F formed in the polishingsurface. Each groove 60F includes a first segment 87A, a second segment87B and an apex 89 where the first and second segments 87A-Binterconnect. During operation, the pad 45F is actuated in the directionV so that the apex 89 points away from the direction of travel and theinitial ends of each of the segments 87A-B lead the apex 89.Accordingly, slurry delivered to the surface of the pad 45F is inducedto flow through the segments 87A-B toward the apex and then onto theupper surface of the pad 45F.

[0048]FIG. 9 shows a cross sectional view of a groove 60. The groove 60is defined by a bottom 90 and two sidewalls 92. While the sidewalls 92are shown here as substantially parallel relative to one another, inother embodiments the sidewalls 92 may be any geometric shape includingtapered, rounded, etc. The grooves 60 have a depth α and a width β.Although variable, in one embodiment the depth α is between about 30mils and about 70 mils and the width β is between about 30 mils andabout 100 mils when the total pad thickness is between about 50 mils andabout 100 mils. Most preferably, the groove dimensions are about 50×50mils on a pad having a thickness of about 80 mils.

[0049] One limitation on the maximum depth α of the grooves 60 is theimpact on the rigidity of the pad. Increasing groove depth α can resultin less pad rigidity. Because rigidity affects the polishing quality ofthe pad 45, the groove depth α should be adjusted to avoid loss ofrigidity. On the other hand, the groove depth α should be sufficient toaccommodate some degree of wear. Over time, continuous polishing willcause the pad 45 to wear resulting in a decrease in the overall padthickness and groove depth α. Thus, in order to avoid prematurereplacement of the pad 45, the grooves 60 are sized to allow asufficient lifetime. The particular groove depth α is dependent on otherpad characteristics, e.g., pad composition and construction, whichaffect the modulus of elasticity.

[0050] While the depth α is preferably constant along the length of thegrooves 60, the invention contemplates having tapered or sloped grooves.The angle of inclination can facilitate slurry delivery control to aparticular area of the pad 45 as determined by the direction of theinclination. For example, the grooves 60 may have an inclination causingthe grooves 60 to become deeper toward the center of the pad 45 or,alternatively, deeper toward the edge of the pad 45. FIG. 10 is a crosssection of a tapered groove 60 taken along the length of the groove 60.As shown, the groove 60 has an inclination angle θ. In one embodiment,the groove 60 may have an inclination angle θ between about 1 degree andabout 0.1 degrees. Because the pad 45 is disposed substantiallyhorizontally during operation the increasing groove depth motivates theflow of fluid toward the center C_(pad) under the influence of gravity.In another embodiment, the grooves 60 may have varying and oppositeangles of inclination so that well areas are formed along the length ofthe grooves 60 which act to collect a higher volume of slurry than atother areas of the grooves 60.

[0051] The foregoing embodiments are merely illustrative and theparticular geometry of the grooves 60 is not limiting of the scope ofthe invention. Any groove design adapted to urge the slurry to aparticular region of the pad 45 is contemplated by the invention.

[0052] In another embodiment, the lower mounting surface of the pad 45is patterned with slurry distribution/retaining grooves 60. FIG. 11shows a perspective cutaway view of the platen 41 having a perforatedpad 45 disposed thereon. The pad 45 can be secured to the platen 41 byan adhesive, such as a pressure sensitive adhesive (PSA). The grooves 60formed on the mounting surface 100 of the pad 45 may be of any geometryand orientation to achieve desired slurry/fluid flow. Accordingly, thegrooves 60 are adapted to cause slurry flow from any point along thegrooves 60 inwardly to a slurry collection area as determined by theparticular groove structure.

[0053] The delivery of the slurry onto the upper polishing surface of apad 45 is facilitated by pores or holes 104 formed in the pad 45. Aplurality of pores or holes 104 formed in the pad 45 extend from thelower mounting surface 100 of the pad 45 to the upper polishing surface102 of the pad 45, thereby providing fluid communication therebetween.The pad 45 shown in FIG. 11 provides a substantially uniformdistribution of pores 104. However, in another embodiment, the locationof the pores 104 may be limited to the location of the slurry collectionarea to further control delivery of the slurry to a defined area. Duringoperation, the slurry is flowed through the grooves 60 due to therotation of the platen 41. As slurry accumulates at the slurrycollection area, the increasing fluid pressure in the grooves 60eventually forces slurry upward through the pores 104 and then onto theupper polishing surface 102 of the pad 45.

[0054] In another embodiment, the mounting surface of the platen 41 ispatterned with slurry distribution/retaining grooves 60. FIG. 12 shows aperspective cutaway view of the platen 41 having a perforated pad 45disposed thereon. Grooves 60 formed on the pad mounting surface 110 ofthe platen 41 are similar in geometry and orientation to the grooves 60Adescribed above with reference to FIG. 3. However, the grooves 60 mayalternatively be any embodiment adapted to deliver slurry/fluid flow toa desired location on the pad 45.

[0055] The grooves 60 are adapted to cause slurry flow from any pointalong the grooves 60 inwardly to a slurry collection area 112 on theplaten 41 and then onto the upper polishing surface 114 of the pad 45.As described with regard to FIG. 11, delivery of the slurry onto theupper polishing surface 114 is facilitated by pores 116 formed in thepad 45 which couple the grooves 60 to the upper polishing surface 114.One perforated pad which may be used to advantage is the IC 1000available from Rodel, Inc. During operation, the slurry is flowedthrough the grooves 60 due to the rotation of the platen 41. As slurryaccumulates at the slurry collection area 112, the increasing fluidpressure in the grooves 60 eventually forces slurry upward through thepores 116 and then onto the upper polishing surface 114 of the pad 45.

[0056] The embodiments shown in FIGS. 11 and 12 are believed to beeffective in avoiding loss of polishing uniformity due to the presenceof grooves on the polishing surface of the pad 45. Where the area of thepolishing surface of the pad 45 occupied by grooves is too great, theability of the pad 45 to uniformly polish a substrate is compromised.Accordingly, providing grooves on the mounting surface of the pad 45and/or the mounting surface of the platen 41 allows the upper polishingsurface of the pad 45 to be relatively planar. However, in otherembodiments, both the upper polishing surface and the lower mountingsurface are patterned with the grooves of the invention. In still otherembodiments, both the upper polishing surface of the pad 45 and themounting surface of the platen 41 are patterned with the grooves of theinvention.

[0057] Where perforated polishing pads are used in combination withgrooves 60 on the lower mounting surface of the pad 45 and/or the uppermounting surface of the platen 41, the grooves 60 preferably extend tothe edge of the pad 45. Thus, the grooves 60 provide pathways betweenthe platen 41 and the polishing pad 45 which vent to the environment ofthe pad/platen assembly. Where the grooves 60 are isolated from theenvironment, such as where the grooves 60 comprise concentric circlesenclosed at the bottom by a platen, a partial vacuum condition may becreated in the grooves as a substrate is urged against the polishing padmaking subsequent removal of the substrate from the polishing pad moredifficult. Although the pores in the pad 45 allow fluid communicationbetween the grooves 60 and the ambience, the relatively small size ofthe pores may prevent quick stabilization of the pressure in the groovesrelative to ambient conditions. By constructing open-ended grooves 60,the grooves 60 remain at equal pressure to the ambient environment,allowing easy removal of the substrate from the polishing pad 45 where aperforated pad is employed. In addition, the open-ended grooves 60 mayalso facilitate removal of the polishing pad 45 from the platen 41.

[0058] It is to be understood that terms such as top, bottom, upper,lower and the like, are relative terms and are not intended to belimiting. Other configurations are contemplated where a substrate can behandled in different orientations.

[0059] While the foregoing is directed to the preferred embodiment ofthe present invention, other and further embodiments of the inventionmay be devised without departing from the basic scope thereof, and thescope thereof is determined by the claims that follow.

What is claimed is:
 1. An apparatus, comprising a semiconductorpolishing device having a first surface defining at least onenon-intersecting fluid retaining groove at least a portion of which isoriented at an angle relative to a radial line originating at a centerof the semiconductor polishing device, wherein the non-intersectingfluid retaining groove is adapted to flow a fluid inwardly toward acenter portion of the semiconductor polishing device.
 2. The apparatusof claim 1, wherein the semiconductor polishing device is one of apolishing pad and a platen.
 3. The apparatus of claim 1, wherein thedepth of the non-intersecting fluid retaining groove changes along alength of the non-intersecting fluid retaining groove.
 4. The apparatusof claim 1, wherein the non-intersecting fluid retaining groove has afirst portion and a second portion having a same direction of curvatureand defining a tangent point to the radial line.
 5. The apparatus ofclaim 1, wherein the non-intersecting fluid retaining groove is orientedin a direction of rotation moving at an increasing radius from a firstend of the grooves to a second end of the grooves.
 6. The apparatus ofclaim 1, wherein the non-intersecting fluid retaining groove is orientedin a direction of rotation moving at an increasing radius along a lengthof the nonintersecting fluid retaining groove.
 7. The apparatus of claim1, wherein the non-intersecting fluid retaining groove is selected fromarcuate grooves, linear grooves, and any combination thereof.
 8. Theapparatus of claim 1, wherein the non-intersecting fluid retaininggroove extends from the center portion of the semiconductor polishingdevice to an edge of the semiconductor polishing device and wherein nopoint of the non-intersecting fluid retaining groove is tangent to theradial line.
 9. The apparatus of claim 1, wherein the semiconductorpolishing device is adapted for use with a rotary polisher.
 10. Theapparatus of claim 1, wherein the semiconductor polishing device isadapted for use with a linear polisher.
 11. The apparatus of claim 1,wherein the semiconductor polishing device is a polishing pad and thefirst surface is a polishing surface.
 12. The apparatus of claim 1,wherein the semiconductor polishing device is a platen and the firstsurface is a polishing pad mounting surface.
 13. The apparatus of claim1, wherein the semiconductor polishing device is a platen and the firstsurface is a polishing pad mounting surface having a perforated paddisposed thereon, wherein a plurality of perforations formed in theperforated pad couple the nonintersecting fluid retaining groove with apolishing surface of the perforated pad.
 14. A substrate polishing pad,comprising: (a) a polishing surface on a first side of the substratepolishing pad; and (b) a mounting surface on a second side of thesubstrate polishing pad; wherein at least one of the polishing surfaceand the mounting surface has a plurality of non-intersecting fluidretaining grooves formed therein, wherein the grooves are disposed sothat upon a given direction of movement of the substrate polishing pad afluid disposed in the grooves is urged to flow from an outer portiontoward a center portion of the substrate polishing pad.
 15. Thesubstrate polishing pad of claim 14, wherein the one or more fluidretaining grooves extend from the center portion of the substratepolishing pad to an edge of the substrate polishing pad and wherein nopoint of the grooves is tangent to a radial line extending from a centerto the substrate polishing pad.
 16. The substrate polishing pad of claim14, wherein the grooves are formed on the mounting surface and thesubstrate polishing pad comprises perforations extending between thepolishing surface and the mounting surface.
 17. The substrate polishingpad of claim 14, wherein the substrate polishing pad comprisespolyurethane.
 18. The substrate polishing pad of claim 14, wherein thesubstrate polishing pad is adapted for use with a rotary polisher. 19.An apparatus for polishing a substrate, comprising: (a) one or morerotatable platens; (b) a motor coupled to the rotatable platens; (c) oneor more polishing heads rotatably mounted in facing relation to therotatable platens; and (d) a polishing pad disposed on each of therotatable platens, wherein at least one of the rotatable platens and thepolishing pads comprise a plurality of non-intersecting fluid retaininggrooves formed on a first surface thereof and wherein at least a portionof the grooves are disposed at an angle to a radial line extending froma center of the first surface and are adapted to flow a fluid inwardlyfrom an outer portion to a center portion of the first surface.
 20. Theapparatus of claim 19, wherein the plurality of non-intersecting fluidretaining grooves comprise a plurality of arcuate grooves extending fromthe center portion to the outer portion.
 21. The apparatus of claim 19,wherein the plurality of non-intersecting fluid retaining grooves areselected from the group of arcuate grooves, linear grooves and anycombination thereof.
 22. The apparatus of claim 19, wherein theplurality of non-intersecting fluid retaining grooves is selected fromthe group of: (a) arcuate grooves; (b) linear grooves disposed in anangular relation to the radial line; and (c) a combination of (a) and(b).
 23. The apparatus of claim 19, wherein the first surface is aplaten mounting surface of the polishing pad in mating abutment with apad mounting surface of the platen and further comprising a plurality ofholes formed through the polishing pad and coupling the plurality ofnon-intersecting fluid retaining grooves with a polishing surface of thepolishing pad.
 24. The apparatus of claim 19, wherein the first surfaceis a pad mounting surface of the platen in mating abutment with a platenmounting surface of the polishing pad and further comprising a pluralityof holes formed through the polishing pad and coupling the plurality ofnon-intersecting fluid retaining grooves with a polishing surface of thepolishing pad.
 25. The apparatus of claim 19, wherein the plurality ofnon-intersecting fluid retaining grooves is selected from the group of:(a) arcuate grooves; (b) linear grooves disposed in non-parallelrelation to a radial line extending from a center of the polishing pador platen; and (c) a combination of (a) and (b).
 26. The apparatus ofclaim 19, wherein the plurality of non-intersecting fluid retaininggrooves comprise a first portion oriented at a first angle greater than0 degrees and less than 90 degrees relative to the radial line and asecond portion oriented at a second angle greater than 90 degrees andless than 180 degrees relative to the radial line.
 27. The apparatus ofclaim 26, wherein the first and second angles vary along theirrespective lengths.
 28. A rotatable platen for a polishing system,comprising a patterned pad mounting surface forming a plurality ofnon-intersecting fluid retaining grooves each having a portion orientedat an angle relative to a radial line originating at a center of thepad, the portion adapted to flow a fluid inwardly from a perimeterportion to a center portion of the platen during rotation of the platen.29. The rotatable platen of claim 28, wherein the plurality ofnon-intersecting fluid retaining grooves is selected from the group of:(a) arcuate grooves; (b) linear grooves disposed in angular relation tothe radial line; and (c) a combination of (a) and (b).
 30. The rotatableplaten of claim 28, wherein a polishing pad is mounted on the padmounting surface so that the polishing pad and the plurality ofnon-intersecting fluid retaining grooves form fluid passageways betweenthe polishing pad and the platen.
 31. The rotatable platen of claim 28,wherein the rotatable platen is part of a chemical mechanical polishingsystem.